Talking true ccTLD's I would rank:
Established:
.de - Classic
.co.uk - Classic
.fr - Fast growing secondary market has been created this year
.ca - Usage in Canada on par with .com and increasing
.All other European ccTLD's, all can be potentially good from traffic and revenue standpoints if researched well enough
.Central / South American ccTLD's growing markets with large potential imo
Ones to stay away from:
.us - will never take off on any scale, .com is too ingrained as usa's ccTLD (just face it already)
.aisa .euro etc, dogs with fleas